Roads could replace solar panels

The UK's network of roads could soon take the place of solar panels if trials of a new technology by the Highways Agency and Transport Research Laboratory are successful. The system, developed by London-based sustainable energy firm Icax, has been designed specifically for UK ground conditions. It uses the surface of roads and motorways to collect and store solar energy in the summer.

On the test project, this energy will be used to keep the test section of road free of snow and ice in the winter. But in the future the stored energy could be used to heat buildings (see "How the Toddington system will work")

Bill Holdsworth, development consultant at Icax, claimed the system would help reduce the number of road accidents and cut congestion. He said: "The technology will keep winter roads dry and free of snow and ice, reduce motorway maintenance and improve road safety. It also promises a sharp reduction in motorway congestion through fewer hold-ups caused by accidents."

He added that the system was cheap and robust: He said: "It is low cost, low maintenance and uses standard industry components."

The designers claim that in the future, the use of a heat pump would mean that the heat stored in the collector array could be used to heat roadside houses, as well as simply keeping the road surface free of ice.

A version of the system is already in use in Zeeland, Holland. This contains a collector array, which transfers heat energy to a store 60 m below ground in a series of aquifers. The system was found to store enough energy to keep the roads free of ice and to heat 100 family homes nearby.

A version of the system has also been specified to heat a new primary school in Hatfield, Hertfordshire. For this project the school's playground will be used to house the solar collector array.

Holdsworth said that in the future collection arrays could be incorporated into buildings, streets and other city surfaces. The ground beneath the city would then become a giant thermal store.

In the UK, construction of the first trial section is underway on a road adjacent to the M1 at Toddington services, Bedfordshire. The trial will be used by the Highways Agency to test two different arrangements � a new build and a retrofit version. Trials are set to begin in June and will last two years.